The present invention relates to a control system for an automatic transmission which includes a solenoid valve for producing solenoid pressure in response to application of a solenoid current thereto, and performs learning control of engagement pressure to be applied to frictional engagement elements which are engaged and released upon shifting.
There have been conventionally proposed control systems for an automatic transmission. Japanese Patent Application First Publication No. 2005-282810 discloses a control system for an automatic transmission which performs learning control of an engagement pressure command value (such as clutch pressure command value and brake pressure command value) that is output until a torque phase is terminated upon the next shifting on the basis of a rate of change of the gear ratio in an inertia phase in order to suppress variation in acceleration of a vehicle from a torque phase to an initial stage of the previous inertia phase.
Japanese Patent Application First Publication No. 2002-276799 discloses a control system for an automatic transmission in which throttle opening TVO (engine load) is divided into a plurality of throttle opening regions and learning correction amounts corresponding to the respective throttle opening regions are set and stored in order to prevent excess or lack of the respective learning correction amounts depending on variation in throttle opening TVO. Upon the next shifting, an engagement pressure command value is corrected by using the learning correction amount corresponding to the throttle opening region which is set and stored at the current shifting stage.